1,179 research outputs found

    International Conference on Shallow-Water Acoustics

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    The conference was jointly organized by the Institute of Acoustics (CAS), Georgia Institute of Technology and Naval Postgraduate School.Shallow water acoustics is currently a topic of great interest world-wide. Strong boundary interaction, multipath propagation and a complex and variable environment make it an extremely challenging field. An international conference could offer the first comprehensive environment in which shallow-water acoustics experts from many nations can exchange information and discuss subjects of common interest.ONR Ocean Acoustics ProgramChinese Academy of SciencesNatural Science Foundation of ChinaChina State Shipbuilding CorporationApproved for public release; distribution unlimite

    TiAIN based nanoscale multilayer coatings designed to adapt their tribological properties at elevated temperatures

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    The addition of properly selected elements, coupled in nanoscale multilayer structures, can further enhance the properties of TiAlN coatings and bring new high performance. The incorporation of Y in the nanoscale pseudo-superlattice TiAlCrN/TiAlYN with typical period of 1.7 nm not only improves the oxidation resistance but also effectively reduces the coefficient of friction of the coating from 0.9 to 0.65 at temperatures in the range of 850–950 °C. The adaptation of the tribological properties occurs as a result of the preferential migration of the Y to the column boundaries. TiAlN/VN superlattice can achieve another self-adaptation process. During friction the coatings adapt themselves to the combined thermal and mechanical wear by the formation of highly lubricious vanadium-oxides due to high flash temperatures at the asperity contacts on the surface. The integrity of the bulk of the coating is retained, leading to exceptionally low, for superhard coatings, friction coefficient of 0.5 and a wear coefficient of 2 × 10−17 m3·N−1·m−1. The coatings have been deposited by the combined steered cathodic arc unbalanced magnetron sputtering method.</p

    Minimalist AdaBoost for blemish identification in potatoes

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    We present a multi-class solution based on minimalist Ad- aBoost for identifying blemishes present in visual images of potatoes. Using training examples we use Real AdaBoost to rst reduce the fea- ture set by selecting ve features for each class, then train binary clas- siers for each class, classifying each testing example according to the binary classier with the highest certainty. Against hand-drawn ground truth data we achieve a pixel match of 83% accuracy in white potatoes and 82% in red potatoes. For the task of identifying which blemishes are present in each potato within typical industry dened criteria (10% coverage) we achieve accuracy rates of 93% and 94%, respectively

    Capacity constrained stochastic static traffic assignment with residual point queues incorporating a proper node model

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    Static traffic assignment models are still widely applied for strategic transport planning purposes in spite of the fact that such models produce implausible traffic flows that exceed link capacities and predict incorrect congestion locations. There have been numerous attempts in the literature to add capacity constraints to obtain more realistic traffic flows and bottleneck locations, but so far there has not been a satisfactory model formulation. After reviewing the literature, we come to the conclusion that an important piece of the puzzle has been missing so far, namely the inclusion of a proper node model. In this paper we propose a novel path-based static traffic assignment model for finding a stochastic user equilibrium in which we include a first order node model that yields realistic turn capacities, which are then used to determine consistent traffic flows and residual point queues. The route choice part of the model is specified as a variational inequality problem, while the network loading part is formulated as a fixed point problem. Both problems are solved using existing techniques. We illustrate the model using hypothetical examples, and also demonstrate feasibility on large-scale networks

    Correlated Electrons Step-by-Step: Itinerant-to-Localized Transition of Fe Impurities in Free-Electron Metal Hosts

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    High-resolution photoemission spectroscopy and realistic ab-initio calculations have been employed to analyze the onset and progression of d-sp hybridization in Fe impurities deposited on alkali metal films. The interplay between delocalization, mediated by the free-electron environment, and Coulomb interaction among d-electrons gives rise to complex electronic configurations. The multiplet structure of a single Fe atom evolves and gradually dissolves into a quasiparticle peak near the Fermi level with increasing the host electron density. The effective multi-orbital impurity problem within the exact diagonalization scheme describes the whole range of hybridizations.Comment: 10 pages, 4 figure

    In-plane and Out-of-plane Plasma Resonances in Optimally Doped La1.84Sr0.16CuO4

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    We addressed the inconsistency between the electron mass anisotropy ratios determined by the far-infrared experiments and DC conductivity measurements. By eliminating possible sources of error and increasing the sensitivity and resolution in the far-infrared reflectivity measurement on the single crystalline and on the polycrystalline La1.84Sr0.16CuO4, we have unambiguously identified that the source of the mass anisotropy problem is in the estimation of the free electron density involved in the charge transport and superconductivity. In this study we found that only 2.8 % of the total doping-induced charge density is itinerant at optimal doping. Our result not only resolves the mass anisotropy puzzle but also points to a novel electronic structure formed by the rest of the electrons that sets the stage for the high temperature superconductivity

    Cell–cell Interaction Underlies Formation of Fluid in the Male Reproductive Tract of the Rat

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    The epithelia lining the epididymides of many species consists of several cell types. We have provided evidence that the basal cells are essential to the integrated functions of the epithelium. Basal cells, but not principal cells, and other cells in the epididymis express TRPC3 and COX-1. We have isolated basal cells from intact rat epididymis using antibody-coated Dynabeads and subjected them to whole-cell patch-clamp measurement of nonselective cation channel activity, a feature of TRPC3 protein, and Fluo-3 fluorescence measurement of intracellular Ca2+ concentration. The results show that a nonselective cation current blockable by La3+ (0.1 mM), Gd3+ (0.1 mM), or SKF96365 (20 μM) could be activated by lysylbradykinin (200 nM). In cells loaded with Fluo-3, addition of lysylbradykinin (100 nM) caused a sustained increase of intracellular Ca2+. This effect was blocked by Gd3+ (0.1 mM) or SKF96365 (20 μM) and was not observed in Fluo-3–loaded principal cells. Stimulation of basal cell/principal cell cocultures with lysylbradykinin (200 nM) evoked in principal cells a current with CFTR-Cl− channel characteristics. Isolated principal cells in the absence of basal cells did not respond to lysylbradykinin but responded to PGE2 (100 nM) with activation of a CFTR-like current. Basal cells, but not principal cells, released prostaglandin E2 when stimulated with lysylbradykinin (100 nM). The release was blocked by SKF96365 (20 μM) and BAPTA-AM (0.05 or 0.1 mM). Confluent cell monolayers harvested from a mixture of disaggregated principal cells and basal cells responded to lysylbradykinin (100 nM) and PGE2 (500 nM) with an increase in electrogenic anion secretion. The former response was dependent on prostaglandin synthesis as piroxicam blocked the response. However, cell cultures obtained from principal cells alone responded to PGE2 but not to bradykinin. These results support the notion that basal cells regulate principal cells through a Ca2+ and COX signaling pathway

    Effect of test conditions on the temperature at which a protective debris bed is formed in fretting of a high strength steel

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    It is well known that mechanisms and rates of fretting wear of many metals are dependent upon the temperature of the environment; specifically, it is known that a transition temperature exists, above which the debris forms a protective bed in the contact which results in very low rates of wear being observed. This paper seeks to investigate the influence of contact geometry and slip amplitude on the transition temperature of a high strength alloy steel, and to understand these effects in terms of debris retention in (or expulsion from) the contact. Cylinder-on-flat fretting tests were performed at temperatures between 25 °C and 250 °C with two displacement amplitudes (25 μm and 100 μm) and two cylinder radii (6 mm and 160 mm). It was found that for the smaller cylinder radius, the transition temperature increased as the fretting displacement amplitude was increased. However, it was found that whilst the contacts with 6 mm radius cylinders and 160 mm radius cylinders exhibited very different mechanisms of wear at low temperature, the temperature at which the transition to forming of the protective debris bed was not strongly influenced by the contact geometry; moreover, at the higher temperature, the protective bed is formed irrespective of contact geometry. It is proposed that the reduction in wear rate at higher temperatures is associated with the retention of oxide debris within in the contact area for long enough that it sinters to form a protective ‘glaze’ layer. By increasing the displacement amplitude, the rate at which the oxide is ejected from the fretting contact increases and this reduces the ability to form a protective layer; as such, a higher temperature is required to form the protective glaze as the displacement amplitude is increased

    Predicting leptonic CP violation in the light of Daya Bay result

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    In the light of the recent Daya Bay result the reactor angle is about 9 degrees, we reconsider the model presented in arXiv:1005.3482 showing that, when all neutrino oscillation parameters are taken at their best fit values of Schwetz et al and the reactor angle to be the central value of Daya Bay, the predicted value of the CP phase is approximately 45 degrees.Comment: 4 pages, 2 figures, update of arXiv:1005.348
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